I. Field
The present disclosure relates generally to communication, and more specifically to techniques for performing cell reselection in a wireless communication system.
II. Background
Wireless communication systems are widely deployed to provide various communication content such as voice, video, packet data, messaging, broadcast, etc. These wireless systems may be multiple-access systems capable of supporting multiple users by sharing the available system resources. Examples of such multiple-access systems include Code Division Multiple Access (CDMA) systems, Time Division Multiple Access (TDMA) systems, Frequency Division Multiple Access (FDMA) systems, Orthogonal FDMA (OFDMA) systems, and Single-Carrier FDMA (SC-FDMA) systems.
A wireless communication system may include a number of cells, where the term “cell” can refer to the smallest coverage area of a Node B and/or a Node B subsystem serving this coverage area. A user equipment (UE) that is just powered on or has just lost coverage may search for suitable cells from which the UE can receive communication service. If a suitable cell is found, then the UE may perform registration with the system via the cell, if necessary. The UE may then “camp” on the cell if the UE is in an idle mode and not actively communicating with the cell. Camping is a process in which the UE monitors a cell for system information and paging information. The cell on which the UE is camped is referred to as the serving cell.
While camped on the serving cell, the UE may periodically search for better cells on the same frequency or another frequency. If a better cell is found, then the UE may select the better cell as a new serving cell via a process commonly referred to as cell reselection. Cell reselection may allow the UE to camp on the best possible cell even as channel conditions change, e.g., due to the UE moving to a new location. This may then allow the UE to reliably receive incoming paging messages and to initiate or receive calls.
The UE may exchange signaling messages in order to perform cell reselection to a better cell. It is desirable to efficiently perform cell reselection in order to reduce the number of signaling messages to exchange and possibly improve system performance.